My knowledge on aircraft engines is limited. So when it comes to engine selection, I was a bit lost. I took time to search through the internet as well as talking to many Cozy builders and fliers to help me make a good choice for my engine.
Other than auto conversion, most builders chose an IO360 instead of an IO320 (though Nat recommended the IO320 in his newsletters). While learning the do's and don'ts from various Cozy builders, I received a quotation from Performance Engines out of La Verne, CA for a Stage III engine overhaul IO320 with verifiable 185HP with his dynamometer. Though I do not quite understand what they do to achieve the higher HP, the idea is certainly inviting... Generally, an IO320 is about 40 lbs lighter that an IO360 (~180-200HP). My wife and I weigh about 300 lbs (together). I think a lighter engine would be good for us because I can potentially reduce another ~13 lbs of ballast up front - resulting in a total 53 lbs overall weight reduction yet performing at the lower HP range of a 360. This sounds like a great option, however, I am concerned only because I have not heard of this configuration before. Upon checking, Performance Engines is a very reputable company and I have no reason to doubt their capabilities.
Here's some details on what they will do: Stage III engine overhaul includes the following: Crankcase: lapped and aligned bored, visual inspection for dimensional and structural integrity and NDT tested. The crankshaft: Magnafluxed, measured for size, reground and heat tested if necessary. Rod and main bearings replaced. Four cylinder assemblies installed. New 10:1 forged pistons. All stress fasteners replaced. Connecting rods rebushed and checked for straightness. Camshaft and lifters are replaced with new. All necessary ferrous and nonferrous parts are NDT tested. Rocker arms are rebushed and ratioed. All aluminum parts are coated with gold irodite and engine is painted in 3 part Epoxy in choice of color. All fasteners are cad plated gold and valve covers, push tubes and intake tubes chrome plated. Accessories included are; Single Lightspeed Plasma III CDI electronic ignition kit + single Slick magneto with plugs & wires (new), B&C high torque starter (new), B&C alternator 12v 60amp (new), FM-200A fuel servo (new) rear facing induction system, fuel flow divider (new), 4 fuel nozzles (new), fuel pump (ovh). Engine functionally tested and tuned for 3.5 hrs., then preserved & crated for shipment. Delivery time 2-3 months. Performance Engines is about 10 miles from me which gives me a bit of a comfort when its time to install the engine. Its warranty does not start until my first flight and is covered for 4 years prorated at 40 hours per month.
I posted a question to the Cozy group and did not get any negative comments to my post, though a couple people still recommended a IO360. I decided to stick with Performance Engines and ordered the engine in August 2009.
After almost 10 months and with a bit of pushing, my engine finally got assembled. Per contract requirement, Performance Engines ran the engine for 3.5 hours on July 2, 2010. Some tuning and adjustment were made during that time. Ron Munson (the owner of Performance Engines) invited me to witness the test run (if I was interested). I drove over to the airport and watched him run the engine with a Club propeller. Supposedly, the Club propeller was designed to apply load to the engine (160HP @2,200 rpm). Ron ran the engine from 600 rpm up to 2,400+ rpm while taking engine performance data at 15 minute intervals. The plaque on my engine is rated at 185HP @ 2,700 rpm. I need to learn how he came to that conclusion / rating. I think this is important when buying the propeller down the road.
Here's another picture of my engine during its 3.5 hours run time. It's loud!
A picture of my engine sitting on an engine stand being prepared for shipping.